Growth of semi-insulating InP with uniform axial Fe doping by a double-crucible LEC technique

The level of an Fe-doped InP melt in a growth crucible is kept constant throughout a Czochralski growth experiment by replenishing it with undoped melt from a second crucible. Since the distribution coefficient of iron is very small (about 0.001), the Fe concentration in the growth crucible is virtually unchanged during the pulling. As a result the ingot obtained exhibits axial Fe concentration much more uniform than in standard LEC crystals. This growth method can increase the yield of semi-insulating InP wafers as it prevents the accumulation of iron and the formation of precipitates in the last to freeze part of the crystal.